Friction, lubrication, and polymer transfer between UHMWPE and CoCrMo hip‐implant materials: A fluorescence microscopy study

Abstract

The friction coefficients of CoCrMo sliding against UHMWPE and CoCrMo were measured in solutions of albumin and synovial fluid containing fluorescently labeled albumin. No fluorescence could be observed on the CoCrMo disc following incubation in labeled albumin or after sliding against CoCrMo. This was due to quenching of the fluorophore by the metal and indicated that a protein film thicker than 10 nm was not formed on the surface. A more complicated behavior was observed for UHMWPE sliding against CoCrMo. For each lubricating solution and at each load, a bimodal distribution of steady-state friction values was observed, the friction coefficient either remaining constant or decreasing during the early stages of the measurement. As no quenching of the fluorophores occurred on the UHMWPE surface, the fluorescence labeling method could be used to reveal polyethylene (PE) transfer and to show that it correlates with the friction coefficient: Low friction coefficients corresponded to a low density of PE spots on the CoCrMo surface. In addition, it was found that the friction coefficients for UHMWPE sliding against CoCrMo in synovial fluid were not significantly different from those in phosphate-buffered saline (PBS), but that the addition of albumin to PBS did cause a significant increase in the friction coefficient.

Highly lubricated polymer interfaces for advanced artificial hip joints through biomimetic design

“…This implies that the presence of protein molecules at the bearing interface increases the resistance to sliding motion. Because proteins are adsorbed on the Co-Cr-Mo alloy counterface, 83,84 the high resistance to sliding motion can be attributed to either a stronger adhesive interaction or to the interpenetration of the adsorbed protein films formed on both the poly(DMAEMA)-grafted X-UHMWPE and the Co-Cr-Mo alloy surfaces. However, the poly(DMAEMA)-grafted X-UHMWPE cups exhibit high wear resistance at high loads during the hip simulator test despite the fact that they show a high dynamic friction coefficient in bovine serum during the ball-on-plate friction test.…”

Wear of CoCrMo alloys used in metal-on-metal hip joints: A tribocorrosion appraisal

“…Papers [78,79] dealing with soft materials (for example UHMWPE) were not included in the table as they did not brought insights into damage of CoCrMo. Table 3 is characterized by a much larger variability of investigated CoCrMo alloys and test conditions compared to simulator investigations (Table 2).…”

The adsorption and lubrication behavior of synovial fluid proteins and glycoproteins on the bearing-surface materials of hip replacements

“…Studies to evaluate albumin adsorption on ceramics and metals have been carried out using XPS and radiolabeling techniques [10,11] as well as sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and chromatography [12,13]. Fluorescence microscopy has been applied to evaluate albumin adsorption on UHMWPE [6,14].…”